Importance

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Abstract

A mobile radio data communication system in which portable radio terminal units transmit a carrier wave modulated with various data and a stationary radio unit demodulates the modulated carrier wave into the transmitted data is disclosed. The data may relate to such aspects of business activities as production, inventory and sale, and are transmitted as analog speech signals. In order to transmit data, the operator presses a transmission key which causes a preamble digital signal and a terminal number digital signal to be successively transmitted. The operator, while pressing the transmission key, speaks into a microphone contained in the portable radio terminal unit. At the stationary radio unit, the preamble digital signal is recognized and the terminal number digital signal is temporarily stored. The transmitted analog speech signals are supplied to a speech recognition circuit which generates a digital speech signal that is stored in a memory. The stationary radio unit then generates a preamble digital signal which is transmitted followed by the temporarily stored terminal number digital signal and the digital speech signal. The portable radio terminal unit corresponding to the transmitted terminal number digital signal recognizes the preamble digital signal and temporarily stores the transmitted digital speech signal. The digital speech signal is then decoded and displayed to the operator. If the speech recognition circuit has correctly recognized the transmitted analog speech signal, the operator presses an acknowledge key. Otherwise, the operator presses a cancel key. In either case, the preamble digital signal and the terminal number digital signals are again successively transmitted. This time, however, these digital signals are followed by an acknowledge digital signal or a cancel digital signal depending on which key was pressed by the operator. At the stationary radio unit, the preamble digital signal is recognized, and if the acknowledge digital signal was transmitted, the digital speech signal stored in the memory is read out to a processor to be edited and printed out as may be appropriate. On the other hand, if the cancel signal was transmitted, the digital speech signal stored in the memory is prevented from being read out and is instead cleared. In this case, the operator must then retransmit the data.

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First Claim